2014 Mercedes-Benz CLA250: Low Tire Pressure Warning

October 7, 2014

Last week I walked down to our office parking garage and jumped in our long-term 2014 Mercedes-Benz CLA250 only to be greeted by a low tire pressure warning light.

That little illuminated yellow "U" with the exclamation point in its center is not exactly what you want to see after a long hard day. After a few curse words, questions started running through my mind.

"Does this car really have a flat tire?"

"Which tire is it?"

"Do I have a tire gauge?"

"Who invented liquid soap and why?"

I was about to jump out of the car and look. Do an old fashioned walk around. But then I realized that this is 2014 and the CLA is, after all, a Mercedes-Benz. I pushed a few buttons on the sedan's steering wheel and I had the answers to three of my questions.

According to the CLA's onboard computer, the car did not have a "flat" tire, but all four tires were low and the left rear was by far the lowest. The spec pressure for the CLA's four tires is 39 psi. At 34 psi, the left rear was low enough to trigger the warning light.

This was good news. Although driving the car on lower than spec tire pressures is not ideal, I now knew I could drive the car safely the short nine low-speed city miles home, where I could pump up the tires to the proper pressures.

I could even monitor the pressures during the drive to make sure the tires weren't losing more air and causing a potentially dangerous situation.

Which is exactly what I did.

Although every new car now sold in the United States has a Tire Pressure Monitoring System (TPMS), some only show the warning light, while others, like the CLA's, can display the actual tire pressures in real time. It's nice to see that Mercedes has equipped its most affordable model with this highly beneficial technology.